topic Re: I am writing an expression in raster calculator, the expression is like: ''1 / 1 + [ Exp * * - ( 10.358 + ( -0.213 * "debrisrast") + ( -0.226 * "frntalrast") + ( -11.172 * "massbrast")]''. It showing an wright expression, but when i run the programm in ArcGIS Spatial Analyst Questions

Help with complex Raster Calculator expression?

LitanMohanty — Fri, 09 Oct 2015 12:38:59 GMT

I am writing an expression in raster calculator, the expression is like:

''1 / 1 + [ Exp * * - ( 10.358 + ( -0.213 * "debrisrast") + ( -0.226 * "frntalrast") + ( -11.172 * "massbrast")]''.

It showing an wright expression, but when i run the programme, it failed. so what might be the problem?

DanPatterson_Retired — Fri, 09 Oct 2015 14:39:10 GMT

Report the error message please and provide details on

what help topics you examined ( ie Exp in spatial analyst )
the source and purpose of the equation and whether this is a verbatim copy from another source
the nature/type of the raster,
the coordinate system,
the location of the source and destination files

curtvprice — Sat, 11 Dec 2021 22:17:06 GMT

This is a valid python expression, but the brackets [ ] don't belong working with rasters.

The usage you are using for Exp tool is invalid, see the help link.

The following is a little more likely to work, though I can't vouch for the results:

1  / ( 1 + ( Exp( -1.0 * ( 10358 + ( -0.213 * "debrisrast") + 
    ( -0.226 * "frntalrast") + ( -11.172 * "massbrast") ))))